1. Field of the Invention
The present invention relates to a load applying device, and more particularly to a magnetic load applying device having a magnetic retarding device adjustable relative to a wheel concentrically.
2. Description of the Prior Art
Various kinds of typical load applying devices have been developed and attached to an exerciser, and comprise a wheel or a disc rotatably supported on a base, and rotated or driven by various kinds of driving mechanisms, such as pedaling mechanisms, and a magnetic retarding device disposed on an outer peripheral portion of the wheel or disc, in order to apply a resistive retarding force against the wheel or disc of the exerciser.
For example, U.S. Pat. No. 4,775,145 to Tsuyama discloses one of the typical magnetic load applying devices for an exercise device and also comprising a magnetic retarding device disposed on an outer peripheral portion of a wheel or disc, in order to apply a resistive retarding force against the wheel or disc, and thus to resist the rotational movement of the wheel or disc. However, the magnetic retarding device is stationarily disposed beside the wheel or disc, and may not be adjusted toward or away from the wheel or disc.
U.S. Pat. No. 4,898,379 to Shiba discloses another typical load applying device for an exercise device and comprising a roller for applying a load to a tire of a rear wheel. The roller is required to be forced against the tire, in order to brake the tire. However, the tire may be forced to move against or to act onto the spindle of the tire, such that a frictional force may be generated or occurred between the tire and the spindle thereof, and such that the spindle may be easily worn out.
U.S. Pat. No. 6,821,236 to Liang discloses a further typical magnetic load applying devices for an exercise device and also comprising a magnetic retarding device including one end pivotally attached to a supporting base, and the other end movable toward and away from the outer peripheral portion of a wheel or disc, in order to apply a resistive retarding force against the wheel or disc, and thus to resist the rotational movement of the wheel or disc. However, the magnetic retarding device is arranged eccentric relative to the wheel or disc, and may also apply an eccentric force against the wheel, such that the frictional force may also be generated or occurred between the wheel and the spindle thereof, and such that the spindle may also be easily worn out.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional load applying devices.